Process of making alkali-insoluble cellulose glycolic acid ether fabric



United States Patent PROCESS OF MAKING ALKALI-INSOLUBLE CEL- LULOSE GLYCOLIC ACID ETHER FABRIC Ladislaus Balassa, West Barrington, and Henry A. Christoph, Norwood, R. L, assignurs, by mesne assignments, to Leslie Ladislaus Balassa, Madison, N. J.

No Drawing. Application June 22, 1949, Serial No. 100,761

6 Claims. (Cl. 8-120) The present invention relates to the partial and uniform etherification of fibrous cellulose by treatment with chloroacetic acid.

Glycolic acid ethers of cellulose have been prepared by the use of chloroacetic acid and sodium hydroxide, and it has been suggested to impregnate cellulosic fabrics with a solution of monochloroacetic acid or a solution of the sodium salt thereof and to then dry the impregnated cloth and causticize it with a sodium hydroxide solution at room temperature for a period oftime from minutes to several hours. Also, it has been suggested to first causticize the fabric and then impregnate it with sodium chloroacetate or chloroacetic acid, following which the fabric thus impregnated was to be heated for a period of time from 10 minutes to anhour at a temperature of 50 to 100 C.

There were serious disadvantages encountered in all of these previous attempts to convert the cellulose fiber into glycolic acid ethers of cellulose. Thus when the free acid was used to impregnate the fabric, it caused severe corrosion of the equipment, and if the acid was dried into. the fabric, it caused considerable lossoftensile strength in the finished product. If the acid-treated goods were causticized immediately after the impregnation, without previous drying,- a product with satisfactory properties resulted but of a much lower degree of substitutionthan one would expect to obtain with the concentration ofs'the acid employed. This meant an. economic loss and a high cost for the process in question.

If the fabric were impregnated with a sodium chloroacetate solution and then dried, the subsequent causticizing of the goods became unpractical becausethe. sodium hydroxide solution did not uniformly wet out the. fabric, and a spotty and uneven treatment resulted which. gave an unsatisfactory product. Attempts were made to partially dry the fabric impregnated with sodium chloroacetate solution before causticizing, but itwas found nonfeasible to partially dry the fabrics uniformly within a narrow range of moisture content. Furthermore, if not completely dry, the sodium chloroacetate hydrolyzed on storage, splitting oif sodium chloride and liberating hydroxyacetic acid.

Wetting agents did not appreciably increase the wetability of the dried sodium chloroacetatc impregnated fabrics when such agents were introduced either into the sodium chloroacetate bath or into the sodium hydroxide solution.

While it is possible to obtain a satisfactory product by first causticizing the fabric and then, without drying, irnpregnating with a chloroacetic acid or sodium chloroacetate solution, this method was found unsatisfactory because of the corrosion of equipment by the acid and the excessive amount of chloroacetic acid or chloroacetate required to obtain a. sufficient degree of substitution. To obtain a substitution ofone glycolic acid group toeach glucose units, it was either. necessary to employ a vast excess of chloroacetic acid or chloroacetate, orit required a correspondingly long reaction time of from 30 minutes to several hours, or even days.

The present invention overcomes the defects of the prior art by employing a solution of the ammonium salt of chloroacetic acid, drying the impregnated fabric completely and then causticizing it with a hot (40 to 55%) sodium hydroxide solution, The dry ammonium chloroacetatecontaining fabric is rapidly and completely wetted by the hot sodium hydroxide solution with evolution of ammonia. Satisfactory degree of substitution, i. e. one glycolic acid group to each 1525 glucose units, was obtained within 45-65 seconds when chloroacetic acid in form of ammonium chloroacetate was used in quantities of 5 to 10% on the weight of the dry fabric. The ammonium chloroacetate-impregnated, fabrics when dried may be stored for prolonged periods of time without showing appreciable hydrolyzation of the chloroacetic acid and consequent loss of reactivity. The maximum rate of reaction was observed when the sodium hydroxide concentration was between 45 to 55% and the temperature of the sodium hydroxide was held between 55 to C.

The following method was used for determining the degree of substitution The treated fabric is rinsed in 2% acetic acid solution and thenin distilled water to remove the acetic acid. The excess water is removedfrom the fabric by centrifuging it in a basket-type centrifuge. The moist fabric, without drying, is then immersed for 24 hours in a 2% copper sulphate solution. The excess copper sulphate is removed by rinsing with distilled water. The fabric is dried by pressing it in a fiat bed press. It is then conditioned for 4 hours in a constant temperature and. humidity room at 70 F. and 65% relative humidity. A suitable sized sample (10-12 gms.) of the copper-containing fabric is then cut into approximately 1" square pieces and the copper extracted from the material with a 5% sulphuric acid solution. The copper present may be: determined either by, gravimetric, volumetric or colorimetric methods. In the present work, the colorimetric method was employed by the use of a suitable electrophotometer. In orderto obtain increasedprecision, the color of the copper solution was intensified with tetraethylenepentam ine. The calculation of the degree of substitution was based on the assumption that each mole of, copper, has combined with 2 glycolic acid carboxyls.

Example I Fabric: Cotton sheeting 39 wide; thread count: 96 x weight: 4.10 yds./lb. The fabric was desized, scoured and bleached before it was subjected to our process.

Preparation of ammonium chloroacetate solution:

. Lbs.

Water 83.25 Monochloroacetic acid Tech. Grade (98%.

ClCH2-COOH) 10.00

Ammonia 26 B. (29.4% NHB) 6.75

Total 100.00

3 immersion, were adjusted to allow a weight of salt solution about equal to that of the weight of the dry fabric to be retained in the fabric. The impregnated fabric, after padding, was dried immediately in a clip-tenter at between 120 to 138 C. for approximately 1 minute. A bone-dry fabric was obtained.

Causticizing.The equipment used for the causticizing was a standard textile padder set for a double immersion and equipped with squeeze rolls between immersions and after the second immersion. A 50% sodium hydroxide solution was used in the immersion tanks as the causticizing liquor. The liquor was heated to about 60 C.

the aid of steam coils in the immersion tanks. ric leaving the padder was picked up in a 20yard long clip-tentcr and held under sufficient weft tension to hold v and held at that temperature throughout the run with The fab-.

causticizing bath, it was squeezed to expel all but about 90 to 110% of sodium hydroxide solution calculated on the weight of the dry fabric.

Washing and drying-The causticized fabric reaching the end of the tenter frame was immediately washed with a very large excess of hot water (80 to 95 C.) and then with cold water in a standard open-width textile washenuntil all excess NaOH was removed. The washing was considered completed when the fabric was neutral to phenolphthalein. The fabric was then dried without tension in a loop drier. Inorder to obtain a fabric with satisfactory dimensional stability, i. e. within 2% shrinkage or stretch, the fabric passed through a tenter frame equipped with steam jets at a tension corresponding with zero width in accordance with established practice in the art.

The'product obtained in the above process was the sodium salt of the glycolic acid ether of the cotton cellulose.

Handle of the fabric:

Stiff, wiry feel Uniformity of treatment:

'Uniform as demonstrated by the even dyeing obtained with methylene blue.

Example ll Fabric: Cotton print cloth 40" wide; thread countz 48 x 48; weight: 2.85 yds./lb. The fabric was desized,

scoured and bleached before impregnating it with the ammonium chloroacetate solution.

The process used in this example was the same as that used in Example I.

Degree of substitution:

1 glycolic ether to 18 glucose units Dimensional stability: 7

Shrinkage'2% after one standard AATCC #3 wash test Tensile strength:

Original fabric, 73 lbs/inch Treated fabric, 90 lbs/inch Elongation at break: 1

Original fabric, 6%

Treated'fabric, 27%

. ing it to our process.

of the sodium salt of Example II.

Handle of the fabric:

Stiff, wiry feel Uniformity of treatment: I

Uniform as demonstrated by even dyeing obtained by the use of methylene blue.

Example III Fabric: Same as in Example II.

Process analogous to Example 11. After washing the fabric free of sodium hydroxide, it was rinsed with an excess of a 2% acetic acid and dried. In this manner, the free glycolic acid ether was obtained. The tensile strength, the elongation and the dimensional stability of the fabric showed only insignificant variations from those The handle of the fabric, however, was full and much softer than that of Example ll. 7

Example IV Example V Fabric: Linen suiting 48 wide; thread count: 25 x 20; weight: 3.43 yds/lb. The fabric was desized, scoured, bleached and mercerized without tension before subject- The process used was the same as in Example 1.

Degree of substitution:

1 glycolic acid ether to l5 glucose units Dimensional stability:

Shrinkage, 4% after test Tensile strength:

Original fabric, 63.27 lbs/inch Treated fabric, 95.9 lbs/inch Elongation at break:

Original fabric, 27% Treated fabric, 19.5% .l-Iandle of the fabric:

Stiff, wiry feel.

one standard AAT CC #3 wash Example VI Fabricsame as in Example V. The process used was the same as in Example IV.

The handle of the fabric in this case was much softer than of the product obtained in Example V.

Tensile strength:

Original fabric, 63.27 lbs/inch Treated fabric, 84 lbs./ inch Elongation at break:

Original fabric, 27% Treated fabric, 10%

The souring of the The sodium salts obtained inaccordance with the above examples are considerably stiffer, more wiry, than the corresponding untreated fabrics. The handle of the fabric is improved if the glycolic acid ether is liberated by souring it with a dilute acid solution and then drying it. The free glycolic acid ether of cellulose has a pleasing handle and shows a fullness and life entirely different from that of the original untreated fabric. The free carboxyl groups are capable of reacting with metals forming colorless or colored compounds depending on the metal. Both the sodium salt and the free acid show exceptionally high degrees of wetability with water. Results similar to those obtained with ammonium chloroacetate were obtained also by the use of the ammonium salts of u-chloropropionic acid and a-bromobutyric acid. Using these longer chain acids, the formation of the glucose ether was somewhat slower and less complete. The products obtained, however, showed uniform treatment. Monochloroacetic acid salts of volatile amino compounds, such as methyl and ethyl amine, were substituted for ammonia in some experiments. The resulting products were similar to those obtained with ammonium chloroacetate. However, the degree of substitution was somewhat less than that obtained with the ammonium salt. The foregoing use of a-chloropropionic acid and a-bromo butyric acid, as well as the monochloroacetic acid salts of volatile amino compounds such as methyl and ethyl amine, are to be regarded in a broad sense as equivalents of the ammonium salts of the monochloroacetic acid.

We claim:

1. A process of preparing alkali-insoluble glycolic acid ethers of fibrous cellulose comprising impregnating the cellulose fabric with an aqueous solution of ammonium monochloroacetate, retaining in the fabric an amount of the solution about equal to the weight of the dry fabric corresponding with to of chloroacetic acid calculated on the Weight of the dry fabric, drying the fabric, impregnating the dried fabric with a 40 to 55% aqueous solution of sodium hydroxide at temperatures about 55 to 85 C., retaining about 90 to 110% sodium hydroxide solution calculated on the weight of the dry fabric, permitting the sodium hydroxide solution to remain in contact with the fabric for a period of from 45 seconds to 3 minutes, removing the sodium hydroxide with excess water, and then drying the fabric.

2. A process of preparing alkali-insoluble glycolic acid ethers of fibrous cellulose comprising impregnating the cellulose fabric with an aqueous solution of ammonium monochloroacetate, retaining in the fabric an amount of the solution about equal to the weight of the dry fabric corresponding with 5% to 10% of chloroacetic acid calculated on the weight of the dry fabric, drying the fabric, impregnating the dried fabric with a 40 to 55% aqueous solution of sodium hydroxide at approximately 60 C., permitting the sodium hydroxide solution to remain in contact with the fabric for a period of from 45 seconds to 3 minutes, removing the sodium hydroxide with excess water, and then drying the fabric.

3. A process of preparing alkali-insoluble glycolic acid ethers of fibrous cellulose comprising impregnating the cellulose fabric with an aqueous solution of ammonium monochloroacetate, retaining in the fabric an amount of the solution about equal to the weight of the dry fabric corresponding with 5% to 10% of chloroacetic acid calculated on the weight of the dry fabric, drying the fabric, impregnating the dried fabric with 40 to 55% aqueous solution of sodium hydroxide at approximately 60 C., retaining about 90 to 110% of sodium hydroxide solution calculated on the weight of the dry fabric, permitting the sodium hydroxide solution to remain in contact with the fabric for about 65 seconds, removing the sodium hydroxide with excess water, and then drying the fabric.

4. A process of preparing alkali-insoluble glycolic acid ethers of fibrous cellulose comprising impregnating the cellulose fabric with an aqueous solution of ammonium monochloroacetate, retaining in the fabric an amount of the solution about equal to the weight of the dry fabric and corresponding with 5% to 10% of chloroacetate acid calculated on the weight of the dry fabric, drying the fabric, passing the dried fabric at a rate of 20 yds./minute through a causticizing bath of 40 to 55 aqueous solution of sodium hydroxide at temperatures about 55 to C., squeezing it immediately as it emerges from the causticizing bath to expel all but about to of sodium hydroxide solution calculated on the Weight of the dry fabric, permitting the sodium hydroxide solution to remain in contact with the fabric for a period of from 45 seconds to 3 minutes, removing the sodium hydroxide with excess water, and then drying the fabric.

5. A process of preparing alkali-insoluble glycolic acid ethers of fibrous cellulose comprising impregnating the cellulose fabric with an aqueous solution of ammonium monochloroacetate, retaining in the fabric an amount of the solution about equal to the weight of the dry fabric and corresponding with 5% to 10% of chloroacetate acid calculated on the weight of the dry fabric, drying the fabric, passing the dried fabric at a rate of 20 yds./minute through a causticizing bath of 40 to 55% aqueous solution of sodium hydroxide at temperatures about 55 to 85 C., squeezing it immediately as it emerges from the causticizing bath to expel all but about 90 to 110% of sodium hydroxide solution calculated on the weight of the dry fabric, permitting the sodium hydroxide solution to remain in contact with the fabric for a period of from 45 seconds to 3 minutes while holding the fabric under weft tension, removing the sodium hydroxide with excess water, and then drying the fabric.

6. A process of preparing alkali-insoluble glycolic acid ethers of fibrous cellulose comprising impregnating the cellulose fabric with an aqueous solution of ammonium monochloroacetate, retaining in the fabric an amount of the solution about equal to the weight of the dry fabric and corresponding with 5% to 10% of chloroacetate acid calculated on the weight of the dry fabric, drying the fabric, passing the dried fabric at a rate of 20 yds./minute through a causticizing bath of 40 to 55 aqueous solution of sodium hydroxide at temperatures about 55 to 85 C., squeezing it immediately as it emerges from the causticizing bath to expel all but about 90 to 110% of sodium hydroxide solution calculated on the weight of the dry fabric, permitting the sodium hydroxide solution to remain in contact with the fabric for a period of from 45 seconds to 3 minutes While holding the fabric under weft tension, removing the sodium hydroxide with excess water, rinsing the fabric with an excess of a weak acid, and then drying the fabric.

References Cited in the file of this patent UNITED STATES PATENTS 1,736,714 Lilienfeld Nov. 19, 1929 2,098,335 Dreyfus Nov. 9, 1937 2,101,263 Maxwell Dec. 7, 1937 2,278,612 Collings Apr. 7, 1942 2,289,039 Reichel July 7, 1942 2,393,562 Perech Jan. 22, 1946 2,448,153 Reid Aug. 13, 1948 2,484,545 Beer Oct. 11, 1949 OTHER REFERENCES Brown et 31.: The Chemical and Physical Properties of Carboxymethylcellulose and Its Salts, Soc. Chem. Ind., Transactions, pp. 254-258, Oct. 1941. 

1. A PROCESS OF PREPARING ALKALI-INSOLUBLE GLYCOLIC ACID ETHERS OF FIBROUS CELLULOSE COMPRISING IMPREGNATING THE CELLULOSE FABRIC WITH AN AQUEOUS SOLUTION OF AMMONIUM MONOCHLOROACETATE, RETAINING IN THE FABRIC AN AMOUNT OF THE SOLUTION ABOUT EQUAL TO THE WEIGHT OF THE DRY FABRIC CORRESPONDING WITH 5% TO 10% OF CHLOROACETIC ACID CALCULATED ON THE WEIGHT OF THE DRY FABRIC, DRYING THE FABRIC, IMPREGNATING THE DRIED FABRIC WITH A 40 TO 55% AQUEOUS SOLUTION OF SODIUM HYDROXIDE AT TEMPERATURES ABOUT 55 TO 85* C., RETAINING ABOUT 90 TO 110% SODIUM HYDROXIDE SOLUTION CALCULATED ON THE WEIGHT OF THE DRY FABRIC, PERMITTING THE SODIUM HYROXIDE SOLUTION TO REMAIN IN CONTACT WITH THE FABRIC FOR A PERIOD OF FROM 45 SECONDS TO 3 MINUTES, REMOVING THE SODIUM HYDROXIDE WITH EXCESS WATER, AND THEN DRYING THE FABRIC. 